Need help with preamplification

Hey Everyone, Im a noob for the most part when it comes to building amplifiers. I have successfully built an amplifier using LM3886. Sounds great. Recently I have built a new amp by bridging the lm3886. I am using my iphone as a music source. My question is this: At some point I must be losing power by running 2 chips on each channel plus a powered subwoofer. What would be a good way to amplify the sound source and maintain sound quality ? Can someone point me in the right direction? Any help would be greatly appreciated.